GOODWILL AND INTANGIBLE ASSETS (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Finite-Lived Intangible Assets [Line Items]
Amortization of intangible assets	$ 369,600,000	$ 275,400,000	$ 243,200,000
Adjustments to intangibles through amortization expense		400,000
Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Asset	9,100,000	10,800,000
Finite-Lived Intangible Assets, Future Amortization Expense
Estimated amortization expense, 2013	237,900,000
Estimated amortization expense, 2014	234,600,000
Estimated amortization expense, 2015	230,000,000.0
Estimated amortization expense, 2016	217,800,000
Estimated amortization expense, 2017	208,500,000
Estimated amortization expense, Thereafter	2,021,900,000
Goodwill, Impairment Loss	0	422,400,000
Goodwill and Intangible Asset Impairment	0	462,100,000	$ 0
Covance Drug Development [Member]
Finite-Lived Intangible Assets, Future Amortization Expense
Goodwill, Impairment Loss	0	418,700,000
Impairment of Intangible Assets (Excluding Goodwill)		31,800,000
Goodwill and Intangible Asset Impairment		450,500,000
Covance Drug Development [Member] | Trademarks and Trade Names [Member]
Finite-Lived Intangible Assets, Future Amortization Expense
Amortization	88.4	27,500,000
LabCorp Diagnostics [Member]
Finite-Lived Intangible Assets, Future Amortization Expense
Goodwill, Impairment Loss	$ 0	3,700,000
Impairment of Intangible Assets (Excluding Goodwill)		7,900,000
Goodwill and Intangible Asset Impairment		$ 11,600,000